30 replies to this topic

[triplebtalk]

Hi all,

Yesterday I was thinking about the theory of time which Albert Einstein came up with, and it got me thinking. Since the speed of light is the fastest speed possible, we could never pass a light beam like we could pass a car on the highway. If we can never pass light, how could we even reach the speed of light? My answer to this would be the fact that the speed of light might be relative to the speed you are moving, hence always being unachievable...

If you think my idea is completely lunatic please tell me, if you think I might have a good point, please help expand on the idea .

Kind Regards,

TriplebTalk

[chaos3932]

So are you saying that the speed of light is relative to time... That it moves and progresses as time does? Or do you mean it is simply relative to our movements? If that is the case then maybe we could acheive light speed. We simply do not have the science developed yet to be capable of harnassing the power needed to propel objects at such speeds. Maybe we cannot move at light speed on earth. However if we were in space could we possibly propel ourselves in some way?

Some people mention G-Force. That we would die if we were placed in a capsule and pushed forward at light speeds. However what if we slowly increased the speed until lightspeed. Just like in a car you feel no oomph when you are driving at 100 miles an hour. Physically you are still and not moving however the car itself is moving you at 100 mph.

[rvalkass]

triplebtalk, on Mar 19 2009, 11:09 AM, said:

My answer to this would be the fact that the speed of light might be relative to the speed you are moving, hence always being unachievable...

The reason the speed of light is so special is because it is not relative. The speed of light is absolute, and does not vary depending on your speed or position.

The reason it is unachievable is because as you approach the speed of light, your mass becomes infinite, and you therefore need infinite energy to move. You could therefore get close to the speed of light, but never actually reach it.

[triplebtalk]

Ok, I will close this idea, I thought I was on to something ...

[cyber_electrons]

rvalkass, on Mar 20 2009, 03:17 PM, said:

The reason it is unachievable is because as you approach the speed of light, your mass becomes infinite, and you therefore need infinite energy to move. You could therefore get close to the speed of light, but never actually reach it.

rvalkass, do you mind if you give some sources for your post? I am really interested in knowing more about this.

anyway....


Let's imagine. If a thing were to have infinite energy to move at an ultimate speed, what then? If the speed of light is a fixed value, then if you are travelling at the same speed (of light) then light would have a relative velocity of zero. But Einstein did say that you will still see light at light speed. What might the conclusion be?

[rvalkass]

cyber_electrons, on Mar 25 2009, 09:23 AM, said:

rvalkass, do you mind if you give some sources for your post? I am really interested in knowing more about this.

My main source is Prof. Bill Barnes who lectured me in relativity I can also explain it using equations, and can give you some background reading if you want to learn about where they come from.

Generally, everyone knows the famous equation E=mc², but this is only half of the equation. The full equation is:

E² = m²c⁴ + p²c²

where E is the energy of your object, m is its mass, c the speed of light and p its relativistic momentum. Relativistic momentum is equal to:

p = (mv)/sqrt(1-(v²/c²))

where v is the velocity of the particle.

Now, as v approaches c, the number in the square root approaches zero, causing the momentum is increase rapidly, towards infinity as v=c. So, at the speed of light, momentum becomes infinite, meaning the energy of the particle must also become infinite.

If any of that made no sense, let me know

[truefusion]

rvalkass, on Mar 25 2009, 03:27 PM, said:

If any of that made no sense, let me know

Though this is not necessarily directed to me (and though it did make sense to me), i am still interested in, or curious about, the implications which jump out at me from your following statement:

rvalkass, on Mar 25 2009, 03:27 PM, said:

So, at the speed of light, momentum becomes infinite, meaning the energy of the particle must also become infinite.

I'll admit i've never done any extensive studies concerning light and its interaction with matter, so if you'll be patient with my questioning, it would be appreciated. Though i'll be alluding mostly to how light interacts with matter and is observed through the naked eye, and though i understand that "light" isn't necessarily something visible though in either case will always be energy, if light as you discuss it is defined as electromagnetic radiation, that is, for example, the light emitted by the sun or perhaps even a light bulb, anything visibly bright so to speak, then i am curious at the length it is emitted at or how something that absorbs light (i.e. if light by nature must be an infinite amount of energy) does not become or obtain the same properities of light, for example, like Moses after speaking with God (Exodus 34:29). Following your statement that the speed of light is absolute, it follows that light is always emitted at its speed (obviously), meaning it would require an infinite amount of energy since its (")entrance(") into reality in order to go the speed of itself. I am curious as to how something infinite can change one of its properties (like not being able to be any longer visible to the human eye) yet maintain its infinite, energetic nature. Likewise, how can an object (or matter) absorb something infinite without itself lasting forever, that is, without "practicing" decay?

But before answering that question, if the object that is emitting light does not within itself contain an infinite amount of energy, then how is it capable of emitting something that by nature is an infinite amount of energy? Or if the object that emits light does indeed posses an infinite amount of energy, then how, for example, can the sun be "scheduled" for depletion or non-existence? Doesn't it follow that anything that produces something infinite must itself be infinite? And that anything infinite cannot itself become finite (over time)? I am uncertain if your courses' studies include how light interacts with matter, or on perhaps heat, etc, or not, but it would be interesting to see what you have to say about this. I do realize i can just go out and attempt to find an answer to all of these questions, that is, that i can just go and research the matter (pun not necessarily intended ) myself, but this way seems more fun.

[rvalkass]

truefusion, on Mar 25 2009, 10:25 PM, said:

I'll admit i've never done any extensive studies concerning light and its interaction with matter, so if you'll be patient with my questioning, it would be appreciated. Though i'll be alluding mostly to how light interacts with matter and is observed through the naked eye, and though i understand that "light" isn't necessarily something visible though in either case will always be energy, if light as you discuss it is defined as electromagnetic radiation, that is, for example, the light emitted by the sun or perhaps even a light bulb, anything visibly bright so to speak, then i am curious at the length it is emitted at or how something that absorbs light (i.e. if light by nature must be an infinite amount of energy) does not become or obtain the same properities of light, for example, like Moses after speaking with God (Exodus 34:29).

Light itself does not have an infinite amount of energy. The energy of a light wave is equal to its frequency multiplied by the Planck constant. This is all to do with the fact that a photon has no rest mass, no size, etc. yet still carries energy, force and momentum. When something absorbs light, it must absorb the energy of the photon. However, it doesn't have to keep it as energy. Rather like in a nuclear reaction, energy and mass are transferrable, so it can be transformed into mass inside the object absorbing the photon.

truefusion, on Mar 25 2009, 10:25 PM, said:

Following your statement that the speed of light is absolute, it follows that light is always emitted at its speed (obviously), meaning it would require an infinite amount of energy since its (")entrance(") into reality in order to go the speed of itself. I am curious as to how something infinite can change one of its properties (like not being able to be any longer visible to the human eye) yet maintain its infinite, energetic nature. Likewise, how can an object (or matter) absorb something infinite without itself lasting forever, that is, without "practicing" decay?

The photon has no rest mass, and changes in energy affect its wavelength/frequency. The more energy you give to a photon, the higher its frequency becomes. As the photon is not infinite in energy, an object simply absorbs whatever energy the photon is carrying at the time.

truefusion, on Mar 25 2009, 10:25 PM, said:

But before answering that question,

Oh well...

truefusion, on Mar 25 2009, 10:25 PM, said:

if the object that is emitting light does not within itself contain an infinite amount of energy, then how is it capable of emitting something that by nature is an infinite amount of energy? Or if the object that emits light does indeed posses an infinite amount of energy, then how, for example, can the sun be "scheduled" for depletion or non-existence?

Again, the photon is not infinite, so your point is somewhat moot. However, the Sun's demise is due to the nuclear reactions going on within its core, and the depletion of its resources. Once the hydrogen, helium and other light elements are fully used up, the Sun will no longer be able to support itself under its own gravity and will heat up rapidly, causing it to expand into a red giant star. The outer layers will then be lost, leaving a dense white dwarf star and lots of stellar gas. The Earth will likely be consumed by the red giant stage. But don't worry - we've got 5 billion years

[cyber_electrons]

What is the answer to this question:

If I am holding a mirror, looking at myself, I would see myself when I am still.

Will I still see myself when I am travelling at the wavefront of light, looking into the mirror?


This is the question in the documentary I saw about e = m c².

If light is a fixed value, then when I travel as fast as light I will not be able to see myself in the mirror as light will never get there. Or is light relative to the speed that I am going? I would still see myself in the mirror even when I am travelling at light speed.

What happens if I try to throw a ball in the same direction that I am travelling at light speed?

[Baniboy]

cyber_electrons, on Mar 26 2009, 04:46 PM, said:

What is the answer to this question:

If I am holding a mirror, looking at myself, I would see myself when I am still.

Will I still see myself when I am travelling at the wavefront of light, looking into the mirror?

One question: where you're holding the mirror? If you're holding it when you're "running" with the speed of light in front of yourself,

At first, yes you will, but when you reach the actual speed of light, light that reflects from your face never reaches the mirror. But if you ask me, you'll die before seeing yourself in mirror.

Quote

Or is light relative to the speed that I am going? I would still see myself in the mirror even when I am travelling at light speed.

No it's not, radiaton always has one direction and can't move to two directions at the same time, it can't move sidewise when it's moving to it's direction. It has no mass, therefore it can never be moved by mass like a physical object, forexample a ball, when you're running and you through it in the air straight up, it will continue it's movement to where you where going AND it goes up. LIGHT DOESN'T.

Quote

What happens if I try to throw a ball in the same direction that I am travelling at light speed?

Well, your mass is relative, you would have to throw the ball faster than the speed of light to even get it out of your hand. And, you can't throw it that hard, it's impossible because nothing can move faster than light. You're already moving with the speed of light, the ball's speed is the same as yours, to throw it, you have to move your hand from back to front and release it, so your hand has to move faster.

Edited by baniboy, 26 March 2009 - 03:59 PM.